In connection with hot melt adhesive or other thermoplastic material dispensing applicator apparatus, wherein the hot melt adhesive or other thermoplastic material is to be sprayed or otherwise dispensed and deposited onto an underlying substrate or product as the substrate or product passes beneath the dispensing valves of the applicators along a product processing line during a hot melt adhesive or other thermoplastic material dispensing application operation or cycle, compressed air is initially conducted into an intake air manifold. This air then needs to be heated and conducted along a passageway which is fluidically connected to the applicator output devices so as to in fact, not only carry the hot melt adhesive or other thermoplastic material out from the dispensing nozzle and onto the underlying substrate or product, but in addition, to heat the hot melt adhesive or other thermoplastic material, to be dispensed, to a predetermined temperature level at which the hot melt adhesive or other thermoplastic material will effectively be rendered sufficiently hot, sticky, and fluid or fluidic so as to in fact be capable of being sprayed or otherwise dispensed onto the underlying substrate or product. Conventionally, the means utilized for the aforenoted heating of the hot melt adhesive or other thermoplastic materials has comprised a suitable heat exchanger. However, conventional heat exchangers have structural limitations. For example, some conventional heat exchangers have baffles and/or machined surfaces incorporated into the heat exchanger structure so as to effectively increase the total surface area of the heat exchanger with which the air, to be heated, will come into contact and be heated thereby. Unfortunately, the surface area of such heat exchangers can only be increased to a certain degree by such structural modifications. In addition, as the number of baffles and/or machined surfaces has been increased, the complexity and manufacturing costs of the heat exchangers become significant factors to be considered from a commercial point of view.
A need therefore exists in the art for a new and improved heat exchanger, for use in connection with hot melt adhesive or other thermoplastic material dispensing applicators, wherein the effective surface area of the heat exchanger is significantly increased so as to enhance the heating efficiency of the heat exchanger, with respect to the air to be heated, such that a greater volume of air can be heated without correspondingly adversely affecting the complexity and manufacturing cost of the heat exchanger.